Apparatus for the producing of aqueous suspensions of clay



March 2, 1943. I H. BRUDAL APPARATUS FOR THE PRODUCING 0F AQUEOUS SUSPENSIONS OF CLAY Filed Dec. 9', 1939 Lila/137m Patented i1 OFFICE APPARATUS FOR THE PRODUCING OF AQUE OUS SUSPENSIO Holger Brudal, Strand, Baerum,

NS F CLAY near Oslo,

Norway; vested in the Alien Property Custodlan Application December 9, 1939, Serial No. 308,484

In Norway December 10, 1938 2 Claims.

This invention relates to the producing of aqueous suspensions of clay. The invention is more particularly concerned with the producing of clay suspensions especially adapted for use as a binding agent for the stabilisation of gravel road surfaces and bases.

For this purpose clay is usually added to the gravel, the gravel and the clay being mixed in special machines. In the mixture thereby obtained, the clay usually appears as more or less rich clay slices or lumps. The purpose of the clay in the stabilised gravel road surfaces is, however, to impart internal cohesion to the gravel mass. In order to fulfill this purpose even the finest particles of the gravel must be coated by a thin film of clay, a purpose which is completely attainable only if the clay is brought into a completely liquid state, as an aqueous suspension wherein the clay is evenly distributed as the finest possible particles.

According to the present invention such finely suspended clay is obtained by cutting the clay into extremely thin slices and small particles by means of a quickly rotating knife device, water being supplied to the clay during the cutting. Preferably a jet of water is directed against the knife device.

Fig. 2 is a vertical cross sectional same, along the line II-II in Fig. 1.

With reference to the drawing l is a supply hopper through which the clay is supplied to a container l, having an outlet, I" through which the clay is forced by means of a rotating feeding device comprising pug mill knives 2 and a feeding screw 3 driven by means of pulley ill. The outlet l" opens into a second container 5, in which the quickly rotating knife device a is arranged, in close proximity to the outlet so as to cut the clay fed through the outlet into very thin slices and small particles. The knife device is mounted in the bearings l2, l2 and is driven by means of the pulley I3. I

The knife device 5 consists of aplurality, for instance four knives of sickle shape, as more view of the clearly shown in Fig, 2, whereby the cutting is The clay to be treated preferably is fed to the knife device from a container through an outlet in the same, in close proximity to which the knife device is located, the clay being forced through the said opening by means'of a suitable feeding device. The feeding device may be of any convenient construction. It may be a rotary device comprising feeding screw or screws, if desired combined with pug mill knives or the device may comprise feeding pistons or the like and be arranged with its axis horizontal, vertical or inclined.

In some cases it may be desirable subsequent to the treating of the clay by means of the said knife device to subject the mass thereby obtained to a further grinding operation in a. grinding mill of suitable construction, for instance a roller, mill, ball mill or the like.

The mass obtained from the knife device {or from the grinding mill may be conveyed to a storing tank of suitable capacity, if desired provided with an agitator.

An embodiment of anapparatus for carrying out the method according to the invention will be described with reference to the accompanying drawing, wherein Fig. 1 is a longitudinal sectional view of the ap-- paratus and facilitated and the clay particles are caused to slide along the knives and be thrown outwardly, thereby preventing a clogging of the clay to the knives. The cross section of the knives may have any suitable shape, for instance as a segment of a circle, as clearly shown in Fig. 1.

The ply pipe it, directing a jet of water against the knife device d. In the embodiment shown the pipe It is directed-in the plane of the knife de vice, but may be arranged at any suitable angle. Y In the container 5 an agitator (not shown) may be provided, preferably'driven by the axle of the knife device. From the container '5 the clay mixture is fed through an outlet 6. Preferably the outlet 6 is arranged in a separate compartment in the container 5 opening at or near-the bottom of the container as shown by 6' in Fig. 2. From the outlet 6 the clay may be conveyed to a grind- 7 ing mill l with bars or rollers 8, which may consist of pipes filled with concrete, in which mill clay which may not yet have been sufiiciently finely divided is further treated so as to produce a satisfactory, even and fine suspension. ,The

, grinding mill 1 is carried by and driven by the i 9 through which the suspension is discharged rotating rollers ll, these rollers preferably being driven by means of a suitable transmission from the main driving source of the apparatus.

The grinding mill l is provided with an outlet andcarried directly to the place where it is to be used or to a storing tank or the like.

The method according to the present invention also has the advantage as compared with previously known methods that the suspension of clay is obtained as a separate product. This is of advantage in case the clay is available near thee 2* container 5 is provided with a water supaccording to the requirements in each case.

The method also facilitates obtaining of an even distribution of clay particles with different degrees of cohesion, an important point if there is the question of mixing clays from difierent sources, or of adding chemicals to the clay.

What I claim is:

1. In an apparatus for the continuous production of aqueous suspensions of clay, especially adapted for use in the stabilization of gravel road surfaces and bases, a container for receiving the clay to be treated, this container having a restricted passage with a substantially unobstructed outlet opening into a second container, and a feeding device in said first-named container for continuousLy pressing the clay through the said passage and outlet in the form of a relatively dry mass, a rapidly rotating knife device mounted inthe said second container in close proximity to the outlet from the first container for rotation in the transverse plane of said outlet, so as to out the clay passing through the latter into very thin slices and small particles, and means for directing a jet of water against the knife device whereby the clay is wet simultaneously with the cutting thereof, so as to form the desired aqueous suspension and also to aid in freeing any adherent particles from the knife device.

2. In an apparatus for the continuous production of aqueous suspensions of clay, especially adapted for use in the stabilization of gravel road surfaces and bases, a container for receiving the clay to be treated, this container having a restricted passage with a substantially unobstructed outlet opening into a second container, and a feeding device in said first-named container for continuously pressing the clay through the said passage and outlet in the form of a relatively dry mass, a rapidly rotating knife device mounted in the said second container in close proximity to the outlet from the first container for rotation in the transverse plane of said outlet, so as to cut the clay passing through the latter into very thin slices and small particles, and means for directing a jet of water against ,the knife device whereby the clay is wet simultaneously with the cutting thereof, so as to form the desired aqueous suspension and also to aid in freeing any adherent particles from the knife device, said knife device comprising a plurality of generally radially extending blades operating in said plane and curved toward their directionof movement in such a manner that the clay particles tend to slide along the blades and to be thrown outwardly.

HOLGER BRUDAL. 

